Motor vehicles such as passenger cars, minivans, trucks, etc., are often shipped or transported from their point of manufacturer to their point of sale (or other intermediate depot) aboard transporter vehicles such as railway cars, car-hauler trucks, ships, barges, and aircraft. During shipping, the motor vehicles are typically secured to the transporter by tie-down chains, cables, or straps. The motor vehicle being shipped is driven onto a generally horizontal deck of the transporter, the tie-down members are attached to anchor points on the deck and on the vehicle, and the tie-down members are tightened to draw the vehicle downwardly toward the deck, compressing the motor vehicle's suspension and thereby firmly restraining the vehicle against undesired motion relative to the conveyance. This tie-down process may reduce the vertical clearance between the lowermost extent of the vehicle underbody and the deck by several inches in comparison with a normal driving configuration of the vehicle.
Many motor vehicles feature aerodynamic devices that extend downwardly from the vehicle underbody to improve vehicle aerodynamic performance, and thereby fuel efficiency. Examples of such aerodynamic devices are numerous, and include front air dams, side skirts, and similar appendages. Such aerodynamics devices are commonly formed of plastic or plastic-composite materials and are designed to be somewhat flexible in order to be resistant to permanent deformation or other damage if they are struck by debris or obstacles on the roadway.
To achieve the maximum amount of improvement in fuel efficiency, it is generally advantageous for an aerodynamic underbody component to extend downwardly as close to the roadway surface as possible when the vehicle is in motion. During shipping of vehicles with low-clearance underbody components, it has been found that the tie-down process described above may cause the underbody component to contact the deck of the transporter. In some cases, this contact may cause damage to the underbody component if the component does not deflect either forwardly or rearwardly in the manner it was designed to operate in normal driving conditions.